PNB 2265 Lecture Notes - Lecture 8: Autonomic Nervous System, Cyclic Adenosine Monophosphate, Myocyte
3 Feb 2017
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If there is more camp, it is faster. Depolarization: funny current: hcn channels close, activate voltage dependent, ca++ channels. Hcn channels and t-type ca++ channels, then l-type channel: close whatever channels bring in positive charge, so calcium. Peak (~20 mv: open k+ channels, inactivate t-type ca++ channels. Repolarization: outward k+ current, open hcn channels to start over. At the end of repolarization, when the membrane potential is very negative (about -60 mv), ion channels open that conduct slow, inward (depolarizing) na+ currents: these currents are called funny currents and abbreviated as if. Cause membrane potential to begin to spontaneously depolarize, initiating phase. 4: as the membrane potential reaches about -50 mv, another type of channel opens. As ca++ enters the cell through these channels down its electrochemical: as the membrane continues to depolarize to about -40 mv, a second ca++ channel opens gradient, the inward directed ca++ currents further depolarize the cell.
